a) Field of the Invention
The present invention relates to a metal golf club head to which a face plate of different material is attached, and, in particular, to an improvement by which a face plate is securely fixed to a golf club head and the attached face plate is prevented from being damaged due to the impact when a golf ball is hit.
b) Description of the Prior Art
Generally, an iron golf club head is formed of a metal such as soft iron and stainless with an integral hosel portion, an integral sole portion and an integral face portion.
The golf club head of this kind has the configuration and weight corresponding to each club number, suffers from a problem that the head is poor in elastic property because the mass of metal, and, in particular, a face portion of the golf club head, which portion is the most important in hitting a ball, is also poor in elastic property. The golf club head of this type is, therefore, poor in repellent property and a soft hit feeling as obtained by a wooden golf club head can not be obtained.
In order to obtain the soft feeling in hitting a golf ball, there has been proposed a golf club head made of metal, to which a face plate made of a fiber-reinforced resin is attached at the face portion, as disclosed, for instance, in the Japanese Utility Model Unexamined Publication Nos. Sho. 62-113570 and 63-68371.
A golf club head disclosed in the Publication No. Sho. 62-113570 is shown in FIG. 7. The golf club head has a notched portion 5 formed in a face portion 3 of a metal head body 1. A face plate 11 made up of a metal base 7 and a fiber-reinforced resin layer 9 integrally secured to the metal base 7, is fitted to the notched portion 5 and secured thereto by fixing the head body 1 to the metal base 13 by a screw 13.
FIG. 8 shows another conventional golf club head disclosed in Publication No. Sho. 63-68371, which has a head body 15 made of metallic material, a recess portion 19 formed in an opposite side of the head body corresponding to a face portion 17, and an elastic member 21 made of fiber-reinforce material. The elastic material 21 is mounted onto a bottom 19a of the recess portion 19, to thereby form a complex-hitting surface portion 23 on the head body 15.
Generally, a disadvantage has been pointed out in the golf club head of this kind such that if a shock or impact caused when a golf ball is hit has been repeated for a long time period of use, then a face plate is damaged and/or broken due to difference in stiffness between the metal head body and the fiber-reinforced-resin-made face plate. Even the golf club head shown in FIG. 7 suffers from the same problem that the face plate 11 is likely to be damaged and/or broken upon the impact of hitting due to the difference in stiffness between the head body 1 or the metal base 7 and the fiber-reinforced resin layer 9.
In the golf club head shown in FIG. 8, the two-layer construction made up of metal and elastic material is formed by mounting the elastic member 21 onto the reverse side of the head body 15 so as to prevent the elastic member from being damaged. Not only it is difficult to obtain a soft hit feeling in comparison with a golf club head in which the face plate is mounted onto a surface of the face portion, but also the elastic member 21 is likely to be damaged and broken due to the difference in stiffness between the metal head body 15 and the elastic member 21 upon shock of the hitting.
Further, since the different materials, i.e. the metal and fiber-reinforced resin are adhered together by adhesive, the resin member is likely to be peeled off from the metal men, bet upon a shock of hitting repeatingly experienced for a long time use.